- Hypothesis-Testing Sub-study (previously labeled small number sSub-studies) is defined as a study with a specific hypothesis to be thattested that can be completed with a few subjects healthy volunteers or patients, , Hypothesis-testing sub-studies will undergo statistical and PIRC review after 6 subjects (if there is one group) or after 12 (six per arm) if two groups are studied before additional subjects are recruited. Together, the P.I. and PIRC will decide whether to continue the hypothesis sub-study with more subjects or if a new protocol is necessary. A memo requesting a review of hypothesis-testing sub-studies for possible additional enrollment will be sent to PIRC and the statistical reviewer. If the action to request accrual increase proceeds beyond PIRC to the IRB, then it needs to be submitted in the form of an amendment for prospective review/approval.